This invention relates to splittable catheters used in procedures for inserting catheters or pacing leads into a human body. A hollow needle that has a coaxial splittable placement catheter thereon is used to penetrate the vein. The needle is then removed, leaving the placement catheter extending through the penetration and into the vein. A catheter, guidewire or pacing lead is then inserted into the vein through the lumen of the placement catheter. The placement catheter is designed to split longitudinally so that it can be removed from the vein without removing the inserted device.
A variety of methods have been used to impart splittability to the placement catheter. For example, in U.S. Pat. No. 4,411,654 issued to Boarini et al, longitudinal lumens or grooves are placed 180 degrees apart into the wall of the catheter during extrusion to provide lines of weakness from the proximal end to the distal end of the catheter along which the catheter will rupture if it is peeled away from an inserted device. A similar effect may be achieved by using a tool to longitudinally score the wall of the catheter after it is molded or extruded. While these methods are generally effective, the lines of weakness provided may be inadequate to provide smooth splittability for the catheter, causing the catheter to tear off of the lines of weakness. Also, if the lines of weakness provided weaken the catheter excessively, it could cause an unexpected rupture of the catheter during the insertion procedure.
It is therefore an object of the present invention to provide a placement catheter that requires reduced force to split the catheter while maintaining the catheter's strength.
It is also an object of the present invention to provide a placement catheter which splits smoothly along lines of weakness in the catheter while minimizing tears off the lines of weakness.